The architecture of high-performance Internet routers has advanced in the last several years to provide increased performance in routing ever-greater volumes of network traffic. It is not uncommon for a router to support numerous protocols as well as several control applications for configuration and maintenance of the router tables, protocols, and network policies. These advances have increased the complexity of the router such that the efficient management of the router's configuration is critical for reliable network performance.
The configuration of a router is typically managed by a centralized configuration database residing on the router. The contents of the configuration database are reflected in the contents of internal data structures in memory that control the operation of the router. Manipulation of the contents of the configuration database and the internal data structures are accomplished with various commands entered using a management interface, such as a command line interface (CLI). Other management interfaces to the configuration of the router include the Simple Network Management Protocol (SNMP), as well as XML-based network management interfaces that use XML to encode configuration data entered by a network administrator via a graphical user interface (GUI), and transmit the data to the configuration database.
Because the configuration of the router is so complex and so volatile, it is important to store the current state of the configuration of the router at a given point in time on a non-volatile storage medium so that the router can be restored without having to re-enter all of the various commands that were used to generate the configuration. In the past the contents of the internal data structures in memory were stored in a binary data file that could be used to quickly restore the memory of the router to the stored configuration. However, the binary data file was not user-friendly as it was not human-readable, and therefore not easily edited. Network administrators had difficulty using the binary files to restore their routers, and often had to prevail upon the network device vendors to provide assistance.
In an effort to overcome this problem, network device vendors began eliminating the binary data files, and replaced them with text-based files in the American Standard Code for Information Interchange (ASCII) format. ASCII is the most common format for text files in computers and on the Internet. In an ASCII file, each alphabetic, numeric, or special character is represented with a 7-bit binary number (a string of seven 0s or 1s). In all, 128 possible characters are defined.
Instead of storing the current state of the configuration from the internal data structures in memory as was done with the binary data files, the vendors use the ASCII text files to store all of the commands that were entered to generate the configuration reflected in the contents of the internal data structures in memory. For example, the ASCII text files might contain various CLI, SNMP, XML, or other types of configuration commands used to generate the configuration of the router. While this provides a way to restore the configuration of the router that is more user-friendly and easier to edit, it also lengthens the amount of time to restore the configuration. For example, the amount of time to restore a typical router from an ASCII text file of configuration commands is often more than four or five hours, because the router has to process each of the various commands in order, just as when the commands were initially entered. Lengthy restoration times are unacceptable for today's 24/7 networks.